Nils Muiznieks, the Council of Europe’s (CoE) commissioner for human rights, on Thursday said he is extremely concerned about the detention of eight human rights defenders in Turkey on Wednesday, calling on Ankara to immediately release them and to end its arbitrary interference with the work of civil society.

“The use of criminal proceedings against human rights defenders for conduct that should be protected under the European Convention on the Human Rights is unfortunately an increasingly frequent phenomenon in Turkey,” said Muiznieks in a statement shared in social media.

“This latest incident further aggravates my concerns in this field, which I have most recently expressed with respect to the proceedings against two prominent human rights defenders, Murat Çelikkan and Taner Kılıç,” added Muiznieks.

“I call on the Turkish authorities to immediately release those detained yesterday [Wednesday] and strongly urge them to stop all arbitrary interferences with the legitimate work of civil society.”

Turkish police, acting on an anonymous tip, raided a hotel on Büyükada, one of the Princes’ Islands off İstanbul, and detained İdil Eser from Amnesty International (AI), İlknur Üstün from the Women’s Coalition, lawyer Günal Kurşun from the Human Rights Agenda Association, lawyer Nalan Erkem from the Citizens Assembly, Nejat Taştan from the Equal Rights Watch Association, Özlem Dalkıran from the Citizens’ Assembly, lawyer Şeyhmuz Özbekli, and Veli Acu from the Human Rights Agenda Association during a digital security and information management workshop.

Two foreign trainers — a German and a Swedish national — as well as the hotel owner, were also detained.

AI Secretary-General Salil Shetty harshly criticized the detention of AI Turkey Director Eser along with seven other human rights activists and two trainers, calling it “a grotesque abuse of power.”

Taner Kılıç, a lawyer and chairman of AI’s Turkey’s board, was arrested on June 9, accused of links to the alleged mastermind of a failed coup attempt on July 15, 2016, Fethullah Gülen, who has denied any involvement.